Nicholas



lama $131125- lgatwt own.

Letters Patent No. 103,879, dated J we '1', 1870; tnzteddt ed May 24', 1870.

jmrnovzinrnooess- FOR MAKING- MoLns'ron ces'rmes or An'ro-nnnrnv rreoans, 8w.

The Schedule referred to in these Letters Patent and making part of the same To all whom it may concern Be it known .that I, NICHOLAS Hers-:rzemmx, of

the city, county, and Stateof New York, have invented a certain new andimproved method or process of preparing or obtaining.duplicate-Molds for making-Composition or otlier-Oast-metal Alto-rethe figure where the sections of the mold join together. The consequence of this is that the figure has to be finishednp by hand to get rid. of this'defee't,; which, in delicately outlined iigures, is attended. with considerable labor, besides adding greatly to thecost of such kiiids of ornamental work.

.By my processfthis ditliulty is entirely overcome, and at the same time great numbers of molds may be duplicated at 'very little cost, and thus large quantitles of the castingsobtained, thereby, by the facility-with which they can be made, cheapening them great-1y.

The nature of my invention consists in the followiug'method or process of preparing the mold for obtaining the casting therefrom.

- I filst form or mold the design 'or figure in wax, or

other plastic or soft material, and take a negative elcctrotype o1: typEmetal shell of it.

lVhen thus electrotyped, the wax or other material used as a modeLis melted, to free itfrom the electrofype, as it willbe obviousthat, as the figure or design is under-cut, the elect-retype would not separate from the mold except by melting it out, as would bethe ease with basso-relievo or open-eutsurfaces, such aswood engravings, 82c. u

M y process in this respect, therefore, differs from the method of obtaining electroypcs geuerallyprac ticed. 1

When the eleetrotype negative shell has'heeu .obtaiued, I next take a copy of it with a gelatine composition, or other equivalent elastic substance.

It will be obvious that this gelatinous substance will readily take 'a perfect impression of the finest tracer-y oflth'e design and its under lines, and when cold retain tli'em, and be readily separated from the electrot-ype without injury, and thus leaving the elec trotype perfect, fromwhich any number of elastic impressions or patterns may be taken.

.When the gelatinous pattern has been obtained, I next take a plaster mold from it. This plaster mold is composed oftwo parts of finely-pulverized brick-dust and one part of plaster of Paris; other similar plasters may be used, as I do not confine my invention to the plaster of which the mold is made, which are mixed in" water quite thinly. 'lhisI apply to the elastic pattern with a soft brush, so as to obtain a perfect mold of the design, and then, when sufficiently backed up, let it stand to harden. When it has become quite hard, the elastic pattern is then separated from the mold.

The mold is now thoroughly dried in an oven, and is then ready for the taking the metal casting therefrom. When the casting has been taken, theplaster inold is separated from the casting by; breaking it to pieces,

or by soaking in. water or other liquid, to dissolve or Another advantage pertaining to my invention is,

that, by the drying out of the gelatinous pattern, it

shrinks or contracts to nearly one half of the original. size of the design. In view of this peculiar property of the gelatinous pattern which I have discovered, I propose to make the castings of the design of different sizes, so as to adapt them' to different articles and uses, by composing the gelatinous pattern of such a consistency as will retain a perfect impression of the figure or design when cold, yet by drying out, will shrink .to the requisite size desired, and thus from the same original model make different sizes of castings therefrom.

Having now-described my invention, 7

I will proceed to set forth what I claim and desire to secure by Letters Patent of the U nitcd States I claim- The method or process substantially as hereinbcfore described, for making molds-for obtaining composition or other soft-metal castings, of alto-relieve or high relief, or under-cut ornamental figures or designs. I

' NICHOLAS HEINTZELMAN. Witncsses:-

CHARLES L. Baum'r'r, .FRANKLIX Bauarrr. 

